{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "1.6.0"
              },
              {
                "fixed": "1.6.11"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0e3f188020fa785d44d0019a3a3c8407a4cc8d5f"
            },
            {
              "fixed": "b4bc65a007784b2eb0efb459e5fa6fd8055d3ec9"
            },
            {
              "fixed": "f41514ef07cfafc5dbf463bd1500aee6575d88a7"
            }
          ],
          "repo": "https://github.com/better-auth/better-auth",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-7w99-5wm4-3g79"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-362",
      "CWE-367"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53518.json"
  },
  "details": "Better Auth is an authentication and authorization library for TypeScript. From 1.6.0 until 1.6.11, the @better-auth/oauth-provider POST /oauth2/token endpoint for the authorization_code grant redeems a single-use authorization code through a non-atomic find-then-delete sequence, allowing two concurrent requests to pass the read step and mint independent access tokens, refresh tokens, and ID tokens; legacy /oauth2/token and /mcp/token paths in oidc-provider and mcp plugins share the same primitive. This issue is fixed in version 1.6.11.",
  "id": "CVE-2026-53518",
  "modified": "2026-07-17T03:42:05.609290568Z",
  "published": "2026-07-15T17:17:06.410Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/better-auth/better-auth/releases/tag/v1.6.11"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53518.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/better-auth/better-auth/security/advisories/GHSA-7w99-5wm4-3g79"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53518"
    },
    {
      "type": "FIX",
      "url": "https://github.com/better-auth/better-auth/commit/b4bc65a007784b2eb0efb459e5fa6fd8055d3ec9"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Better Auth OAuth Provider: Race Condition in Authorization Code Exchange Enables Multi-Use Code Redemption"
}